.back-top {
    display: none;
     position: fixed;
     top: 10px;
     right: 300px;
     display: flex;
     flex-direction: column;
     background-color: #ffffff;
     width: 50px;
     border-radius: 10px;
   }
   .back-top > div {
     justify-content: center;
     width: 50px;
     height: 50px;
     padding: 10px;
     font-size: 12px;
   }
   .back-top > div:hover {
     background-color: #ff5000;
     color: #ffffff;
     font-weight: bold;
     border-radius: 10px;
   }